This invention relates to dispensing of liquid petroleum gas (LPG) and more particularly to methods and apparatus for dispensing of propane gas to motor vehicle tanks and to portable bottled gas containers.
xe2x80x9cPropanexe2x80x9d strictly speaking relates to a specific alkane hydrocarbon compound of the same family as methane, ethane, butane and others. Propane is a component of natural gas, and it can be separated from other components by compressing and cooling the natural gas mixture until propane becomes liquefied. Propane is also obtained as a by-product in fractional distillation of petroleum. The liquefied gas from these sources is sold commercially as bottled gas fuel distributed to customers in small portable containers and as a motor vehicle fuel used in engines adapted for this purpose.
Commercially available propane fuel is conventionally designated as xe2x80x9cpropanexe2x80x9d despite small amounts of other gasses such as methane, ethane, butane and other hydrocarbon gasses mixed with the propane. Up to about 5% or so (in the United States) of such other components may be included. In the present application, it is to be understood that xe2x80x9cpropanexe2x80x9d is intended to refer to commercially available fuel mixtures so designated which may include other gasses.
Although the composition of propane fuel as bottled gas and motor fuel applications may be the same in each case, the apparatus and method used in measuring the amount dispensed and determining the price to retail customers varies significantly. Bottled gas fuel is stored and transported in pressurized, portable metal cylinders which typically hold anywhere from about 2.5 pound to 100 pounds of gas. Many of the customers for bottled gas fuel are owners of recreational vehicles such as motor homes and trailers who take advantage of the convenience afforded by the portability of this fuel. Filling of bottled gas containers is generally carried out as a refilling service at a standard charge based on the amount of liquified gas needed to fill an empty tank. This type of service does not take into account residual amounts of liquid gas in the container, meaning that the customer pays more per unit of liquified gas received if the tank is not empty. Completion of filling is determined by weight, which requires the presence of a suitable scale. Propane motor fuel, on the other hand, is dispensed and sold in certain areas of the country in much the same manner as gasoline and diesel fuel, that is by dispensers installed at filling stations, the dispensers metering purchased fuel by volume and automatically displaying the price, based on gallons delivered. In many instances, propane is sold both as bottled gas and motor fuel at the same retail establishment, which may be a convenience store or filling station. Here, vehicles are typically fueled at a service island, while the bottled gas refueling facility is a separate facility some distance away from the service island. Under these circumstances, it would be advantageous to provide an integrated propane dispensing facility which would enable serving both markets and which would use, to the extent possible, the same equipment for both.
The present invention is directed to a dual purpose propane dispensing system comprising apparatus appropriate for a bottled gas dispensing station disposed in an enclosure on one side of a supporting frame and a propane motor vehicle dispenser disposed on the other side thereof or in close proximity thereto. The system is adapted for installation on a common service island of a filling station and for being connected to a propane supply line provided at the island. A scale and a pressurized dispensing nozzle coupled to the supply line are housed in the enclosure on the bottle gas side, the enclosure provided with a lock securing the nozzle when not in use. The propane motor vehicle fuel dispenser on the other side may have the same fuel delivery features as in previously known propane dispensers, but is modified to enable input data obtained from flow of bottled gas to be fed into the electronic metering and price display components of the dispenser so as to provide a display of the price for dispensed bottled gas. Flow of fuel from the supply line to the selected nozzle, either the bottled gas nozzle or the motor vehicle dispenser nozzle, may be controlled by switching of solenoid-actuated valves controlling flow to the nozzles. Price calculations made by the computer may be controlled to reflect the different tax treatment of motor vehicle fuel and bottled gas.
The dual purpose system of this invention is designed for preassembly at a factory or shop, with only the steps of bolting the supporting skid to a concrete pad of a service island, making connections to a liquid supply line, vapor lines and an electrical source being required.
This system also provides a complete retail propane refueling system at a single location, allowing bottled gas containers and motor vehicle tanks to be filled quickly and conveniently. Further advantages are provided by the rugged construction and professional appearance presented to the customer. Unlike prior practice, this approach also provides a fairer result to those seeking bottled gas by only charging for the amount of fuel delivered.